This invention relates to a wind energy power system of the type using a multi-blade propeller for producing power from wind energy. Such systems typically employ a multiblade, wind-driven, variable pitch propeller supported at the top of a tower and connected through a direct drive or speed increaser or other arrangement for driving an output shaft supported on the tower. The output shaft may be connected to power a pump for pumping water or other material, or for operating a compressor for refrigeration or other uses, or for the production of mechanical power or electrical energy for any desired use. More particularly, the invention relates to a damping apparatus for damping pitch change movement of the propeller, and represents an improvement over the structures described in applicant's earlier patents 2,505,969 and 4,068,131.